An evaluation of the use of the URET prototype tool at Indianapolis and Memphis air route traffic control centers, using benefit metrics

The user request evaluation tool (URET) conflict probe is a software tool developed to alert air traffic controllers to potential strategic conflicts between controlled flights. URET builds four-dimensional trajectories of flights and notifies a controller when two flights are predicted to come within separation tolerances. URET also allows controllers to build trial plans to find a conflict-free and efficient resolution. These capabilities have created benefits for the flying community. A prototype of URET was installed at the Indianapolis and Memphis ARTCCs early in 1997. Metrics to determine the benefits from using URET at these centers, under normal operational conditions, have been analyzed since January 1999. (These metrics were selected for study in the free flight phase 1 metrics plan (Federal Aviation Administration, Aug. 1999)). This paper presents the mechanisms for calculating the metrics and describes the results, particularly noting the trends in the metric values over time.